Conventional microbiological safety cabinets generally have a fixed operating unit installed that is usually mounted on the outside of the housing. For example, such a safety cabinet is described in the applicant's DE 4441784 C2. To use the functions of the safety cabinet while working, the user must remove his hands from the internal workspace enclosed by a housing. In the process, traces of the microbiological cultures being handled in the workspace can be inadvertently brought to the exterior on the hands and cause contamination there. Conversely, it is possible when using the nonsterile operating element outside the housing for contaminants to be brought into the interior of the safety cabinet. In the worst case, this can lead to damaging of the cultures being handled and to falsification of the experimental results.